Hardware Sensors provide you CPU Temperature on Unity panel. This indicator shows CPU Fan Speed, CPU Temperature, GPU Temperature, Which can be very useful for everyone if your pc is overheating it will show you temperature. It depends on your hardware if you have sensors it will show everything.
Here are more indicators for your Ubuntu/Mint.
To install indicator sensors in Ubuntu/Mint open Terminal (Press Ctrl+Alt+T) and copy the following commands in the Terminal:
Source: launchpad alexmurray